Alkyl-sulfoxide and alkyl-sulfone terminated oligomers

ABSTRACT

Alkyl-sulfoxide and alkyl-sulfone terminated oligomers. Prepared by addition polymerization of monomer in presence of a mercaptan, followed by oxidation. Oligomers used as emulsifiers in the emulsion polymerization of one of more monomers to produce rubber or plastic latexes from which solid polymers can be obtained.

United States Patent Dannals 1 June 6, 1972 [54] ALKYL-SULFOXIDE AND ALKYL- 3,498,943 3 1970 Dannals ..260/29.6

SULFONE TERMINATED OLIGOMERS OTHER PUBLICATIONS [72] Inventor: Leland E. Dannals, Waterbury, Conn.

Reid, Organic Chemistry of Bivalent Sulfur," 1960, Vol. II, [73] Assignee: Uniroyal, Inc., New York, NY. pp, 64. 65 [22] Filed: N0 19, 1968 Kharasch, Organic Sulfur Compounds," 1961, Vol. I, pp.

229 and 244 [21] Appl. No.: 777,175

Related US. Application Data Primary ExaminerJoseph P. Brust Att0rneyBert J. Lewen [63] Continuation-impart of Ser. Nos. 547,743, May 5, V W n I966, abandoned, and Set. NO. 562,097, July 1, I966, 57 ABSTRACT Pat. No. 3,498,943, and Ser. No. 562,098, July I, 1966, Pat. No. 3,498,942. Alkyl-sulfoxide and alkyl-sulfone terminated oligomers. Prepared by addition polymerization of monomer in presence I Q, of a mercaptan, followed by oxidation. Oligomers used as 260/29-6 260/29-6 260/29-6 AN, 260/293 emulsifiers in the emulsion polymerization of one of more 260/29-7 260/297 260/4299 260/4656 monomers to produce rubber or plastic latexes from which 260/5 37 solid polymers can be obtained. [51] Int. Cl. ..C07c 121/28, C07c l21/38,C07e 121/40 [58] Field of Search ..260/465.4, 607 A, 465.6, 326.5, 260/3263, 48], 488, 534, 537,561, 429.9

[56] References Cited 12 Claims, No Drawings 4 UNITED STATES PATENTS 3/1970 Dannals ..260/29.6

ALKYL-SULFOXIDE AND ALKYL-SULFONE TERMINATED OLIGOMERS CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. application Ser. No. 547,743 filed May 5, 1966, and entitled Oligomers," now abandoned US. application, Ser. No. 562,097 filed July 1, 1966, entitled Emulsion Polymerization, now US. Pat. No. 3,498,943 and US. application, Ser. No. 562,098 filed July I, 1966, entitled Emulsion Polymerization," now US. Pat. 3,498,942. The contents of each of said applications are incorporated by reference herein.

BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to alkyl-sulfoxide and alkyl-sulfone terminated oligomers, to their preparation, and to their use as emulsifiers in emulsion polymerization,

2. Description of the Prior Art In the foregoing cross-referenced applications there are described alkyl-sulfide terminated oligomers, the preparation of such oligomers, and their use in emulsion polymerization. Where such oligomers are used in emulsion polymerization to produce rubber latexes, it frequently has been found that, at a given turbidity and solids content, the latex has a higher viscosity than would generally be advantageous. Thus, it would be desirable to obtain rubber latexes showing relatively lower viscosities at such turbidity and solids content. In addition, latexes prepared using conventional emulsifiers tend to foam, which impedes the removal of monomers and water therefrom and is generally disadvantageous. Hence, a latex that exhibits little or no foaming would be highly desirable.

SUMMARY OF THE INVENTION This invention relates to oligomers, to a method of their preparation, and to their use, as in emulsion polymerization and the like. More specifically, the invention relates to oligomers having a backbone of carbon atoms and appendant polar groups. The oligomers of the invention may be used as surface active agents, emulsifiers or thickeners.

The oligomers of this invention are alkyl-sulfoxide or alkylsulfone terminated compounds having a backbone of from four to I carbon atoms in addition to those of the alkyl group. Attached to the oligomeric carbon atoms are appendant polar groups. At least one polar group is present for each two carbon atoms in the chain.

Generically, the oligomers may be represented by the following formula:

It is to be understood that the foregoing formula is not intended to depict the actual structure of the final compounds, inasmuch as structural units are randomly distributed in the molecule.

In the above generic Formula (I), R is an alkyl group having from about five to 20 carbon atoms, or mixtures thereof; Z is oxygen or nothing; R and R may each be hydrogen, methyl, ethyl or -COOH groups; R and R each may be hydrogen, methyl, ethyl, -COOI-I or --CI-I COOI-I groups; Y is a strongly hydrophilic group such as -COOH, CONI-I OCH3, CHQOH, OC2H5, or

and X is either one of the aforesaid strongly hydrophilic groups or is a less hydrophilic group such as COOC I-I OI-I,

There must always be at least one strongly hydrophilic group, Y, present, but there need not necessarily be a less hydrophilic group, X, in which case a in Formula I will be zero.

The foregoing oligomers may be prepared by addition polymerization of suitable monomers in the presence of alkyl mercaptans, followed by oxidation, as with hydrogen peroxide or ozone.

The alkyl-sulfide or alkyl-sulfone terminated oligomers have particular application as emulsifiers in the emulsion, addition polymerization of various monomers to produce rubber and plastic latexes from which solid polymers may be acquired.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As previously noted, the oligomers of the invention are alkyl-sulfoxide or alkyl-sulfone terminated compounds having a backbone of from four to carbon atoms in addition to those of the alkyl group. Attached to the oligomeric carbon atoms are appendant polar groups. At least one polar group is present for each two carbon atoms in the chain. The oligomers are generally water soluble, either by themselves or as the corresponding alkaline salts.

The method of preparing these oligomers results in a product having a very narrow molecular weight distribution. Thus, the polydispersity index, Mw/Mn, is always less than 2 and frequently as low as 1.4 to 1.5, as determined by the Ge] Permeation Chromatographic technique.

Generically, the oligomers may be represented by the Formula (I):

As noted, it is to be understood that the foregoing formula is not intended to depict the actual structure of the final compounds, inasmuch as the structural units It It: R3 R4 l-C and C-X- III 1 III Y are randomly distributed in the molecule.

In the above generic Formula (I), R is an alkyl group and may be a straight chain primary (normal), branched chain primary, secondary or tertiary alkyl group having from five to 20 carbon atoms, and preferably six to 12 carbon atoms, or mixtures thereof; Z is oxygen or nothing; (where Z is nothing, then the oligomer is alkyl-sulfoxide terminated; where Z is oxygen, then the oligomer is alkyl-sulfone terminated); R and R may each be hydrogen, methyl, ethyl or -COOI-l groups; R and R may each be hydrogen, methyl, ethyl or COOI-I or Cl-I COOI-l groups; Y is a strongly hydrophilic group such as COOH, -CONI-I --OCI-I --OC I-I -CI-I OI-I,

and X is either one of the aforesaid strong hydrophilic groups or is a less hydrophilic group such as COOC I-l.,OH, COOC I-I OI-I, CONI-ICH OI-I, -CONI-ICI-I CONHC I-I CONI-IC H -COOCI-I -COOC H -CN, OOCCI-I OOCC I-I or There must always be at least one strongly hydrophilic group, Y, present, but there need not be a less hydrophilic group, X.

The degree of polymerization, a b, should be between about 2 and 50, and preferably between about 3 and 30. The mole fraction of the monomer having the X functional group a/(a+b), may vary from to 1 unless X is a less hydrophilic neutralized, as with ammonia, substituted ammonium compounds or alkali metal hydroxides.

Another preferred class of oligomers has the formula:

RS(O) (CH CHCN ),,(CH CR,COOH) -H|n group, in which case the mole fraction must be less than 0.6, wherein R is a primary or secondary alkyl group having from and preferably less than 0.55. The ratio of a to b may be varied about six to 12 carbon atoms, preferably a normal alkyl group as desired by those skilled in the art, depending, most imporhaving from about seven to l 1 carbon atoms, and most tantly, on the desired water solubility of the oligomer or its desirably, from about eight to carbon atoms; c is an integer, salts. For example, where the less hydrophilic group is either and is either l or 2; R is either hydrogen or methyl; a b. the CN or CONHCH OH, the mole fraction is most desirably 10 degree of polymerization, is from about 4 to 50, preferably fr 0.3 to 0.5. On th h r h d, wh one f the other l from about l2 to 30: and u/(u-Hrl is O to 0.6 and preferably 0.2 hydrophilic groups is present, the preferred mole f ti i to 0.55. For use as an emulsifier, this class of oligomers may be less than 0.3. converted to the water soluble salt, e.g., ammonium or alkali The molecular weight of the oligomers of this invention metal Salth l be less than 5 000 r f r bl less than 2 000 but Afurther preferred class of oligomers has the fonnula: higher than 200. RS(O)(CH CR,COOH -(CH CRgC0NHg)b (IV The oligomers of this invention are soluble in water or are Where R is a primary or secondary alkyl group, preferably a readily made soluble in water by conversion to salts, as by normal alkyl group having from about 6 to carbon atoms, reaction With the app opri metal OXide, metal y i e, 20 and most preferably from about 7 to l2 carbon atoms; R, is ammonium J) hydroxide, amine, etc. While the m either hydrogen, methyl or CH COOH; R2 is hydrogen or um, substituted ammonium, and alkali metal salts are broadly methyl; 11+ [1, the degree of polymerization, is about 6 to 50, soluble, the alkaline earth metal and Group III heavy metal and preferably from about 12 to 30; and u/(a-l-b) is from Salts y e be soluble, p h' m the case Of the about 0.075 to 0.40, and preferably from about 0.075 to 0.30. oligomers PE two-Strongly y p g fp When a monofunctional acid is present the upper portions Salts p l mterest are l of sPdlum, Potasslum, of the ranges are preferred, while for a difunctional acid the ammemum, Calelum, i g l barium, and the f lower portions are preferred. Since this class of oligomers alkyl l alkfmol Subsmuted i w menoethenolammeis water soluble, they may be used in their acid form or may n Skilled the art y y determine Whlch of the be converted into their water soluble salts as previously oligomers of the invention and which of their salts are water described 7 soluble. A particularly preferred class of oligomers whlch are The oligomers ofthis invention are prepared by the addition useful as emulsifiers has the formula: polymerization of appropriate monomers in the presence of RS(O)'(CHZ CRICOOH)V H (H) alkyl mercaptans, and this is followed by oxidation, as with wherein R is an alkyl group having from about six to 12 carbon hydrogen peroxide or ozone Use of hydrogen peroxide atoms Preferably a normal alkyl group llavmg from about ozone as the oxidizing agent is preferred because they form no f to 11 Carbon atoms f most deslrably from about acid or salt byproducts, which byproducts might possibly have eight to 10 carbon atomsyR, s either hydrogen or methyl; and an adverse effect on latex properties and ultimate product perthe degree of Polymenzanon, about 2 to Preferably formance. The use of potassium persulfate would form from about 2 to 30, Preferably from about 3 to sulfates, while halogens would be converted to halides. For use as an emulslfief, thls Class of ollgomers y be used Typical examples of the oligomers of the present invention wherein only a small percent of the acid groups have been ihdude the f ll i -H) fl/( 3 0 1 n-CaH17S (O)-- -CIIz-(l3I-I---- ---H L C 0 0 H |3 3 2 n-CsHnS )T-- --CH2-]CH--- --H 0 L C OOHJ,

F 4 0 3 n-CaHnS (O)-- CHz-CH -'--H C O OI-I 4 6 0 4 sHn CH2$H--- H C O OH 5 10 0 5 -csHn (O)---"CH2(I3H H C O OHJIO 1 I 3 0 6 n-CaH11S(O)--CHzC H C O OH I 3 0 7 p-CsH17S(O)---CH2-(EH H C O OIL-L 3 0 8 t-CaHnS(O)--- CH2-(EH--- --H L C O 0 Hi3 r I 3 O n-CmllnS(O) "CllzCll ll J L moon I! /(a-Hz) l0"... n-cuHns(oycnzcn- -n 3 0 L (ITOOH a 11... n-C;H 1S(O)-- CHzCH'- --CHr-cH- fi 16 L (IIN JEL (|ZOOH L l2... n-CaHnS (O)r- CI-IrCH--- -CH2-CH-" -H 16 0.50

L on .L L ("JOOHJ:

1a,... n-CH21S(O)"' CH2-CH" --CH2-CH--- --H 30 L (IN .JwL boonlw 14 n-CmHnS(O)-- CHiCH CHi-CH-- --H 16 0.50

L INJa L (IIOOHJ! I- CHzCOOHI I'- I H-CQHnS(O)-----CHz-( J -----oH,-oH --H 20 0.10

L boon L lONHziis I- onicoorr" 1 1e..... n-crn5s(o -----orn- "om-ca -11 20 0.10 L COOH J2 L JONHLJIB CHzCOOH] l" 11...- n-CiH11S(O)----CHr- C -CHrCH --H 20 0.20

L ICOOH |4 L CONHJIO cmcoorr! '1 1s.... l'l-CsHns (O)----CHz- "Caron -H 40 0.10 L coon .J; L JONHzJn carooon-l l 19..... r-ciuwswronrc euron --H 20 0.10

00011 .L L. coward" 20"..- n-CsHnS(0)" CH2CH-'- CH1CH -11 20 0.20 L boom]; L boNHJ" 21... D-CI2H25S L COOHJ JONH L Thus, suitable monomers used in preparing the oligomers of this invention include acrylic acid, acrylonitrile, acrylarnide, itaconic acid, methacrylic acid, methacrylamide, and the like, as well as mixtures thereof.

As previously noted, the oligomers of the present invention may be prepared by the addition polymerization of appropriate monomers in the presence of alkyl mercaptans, followed by oxidation with hydrogen peroxide or ozone. As described in my copending application, Ser. No. 547,743, the addition polymerization results in an alkyl-sulfide terminated oligomer of the formula per mole equivalent of sulfur. When the sulfone is desired, two

mole equivalents of the hydrogen peroxide or ozone are employed per mole equivalent of sulfur.

The oxidation is conveniently carried out at a temperature from about 30 to 90 C., and preferably from about to 70 C. The reaction time may vary widely, e.g., from 1 hour to 24 hours. in general, the lower the temperature, the longer is the time required. Preferably the reaction time is from about 1 to 2 hours.

inasmuch as the alkyl-sulfide terminated oligomer is water soluble, either as is or as the alkali metal salt form, it is convenient to carry out the reaction with the oligomer in aqueous solution. The concentration of oligomer in the solution is desirably from about 10 to 50 percent by weight, and preferably from about 30 to 45 percent by weight.

When hydrogen peroxide is employed as the oxidizing agent, it is generally preferred to use an aqueous solution thereof. When ozone is employed as the oxidizing agent, it is usually advantageous to use an air-ozone stream.

The method of producing sulfoxide-terrninated sulfoxideterminated and sulfone-terminated oligomers of the present invention is further illustrated by the examples hereinafter. See particularly Examples l-lll.

The present invention also relates to the use of the instant alkyl-sulfoxide or alkyl-sulfone terminated oligomers as emulsifiers in the emulsion, addition polymerization of monomeric materials to produce rubber and plastic latexes from which solid polymers may be obtained.

In emulsion polymerization, the emulsifier plays a key role, not only in the polymerization itself, but also in the finishing of the latex and in its resultant properties. Because of the need to use existing resources as efiiciently as possible, the rate of polymerization is a most important factor. it is also highly desirable that the emulsifier form a latex that is (1) low in macroscopic discontinuities, such as grain, coagulum, or microfloc, which cause manufacturing difficulties and reduce product utility, (2) low in foaming, as this would tend to obviate the need for antifoaming agents, (3) of small particle size or of low turbidity, inasmuch as this increases productivity and is also beneficial to ultimate use, (4) of low viscosity, since this makes for efficient transfer without hold-up losses, (5) of high latex solids concentration, since this increases productivity and decreases transportation costs, and (6) of good mechanical stability, for instance, giving low values in the S-l test, since the latex must stand up against deterioration on storage, transport, compounding, and use. (In the S-l test, the latex is stirred at a standard speed of 15,000 rpm for 30 minutes, using a Hamilton Beach Mixer. At the end of the stirring, the latex is filtered through 100 mesh screen and the retained coagulum dried and weighed. The S-l mechanical stability of a latex is reported as percent of dry coagulum found during stirring, based on latex weight.)

The emulsion polymerization of the instant invention may be applied to the preparation of a widevariety of addition polymers. These polymers are formed by the polymerization of l copolymerizable monoethylenically unsaturated monomers and (2) of conjugated diolefinic monomers. Among the conjugated diolefin polymers and copolymers are polymeric materials from butadiene, butadiene-styrene, butadiene-acrylonitrile, butadiene-vinylidene chloride, butadiene-methacrylonitrile, and the like. The polymers and copolymers from monoethylenically unsaturated monomers include polymeric materials from styrene, styreneacrylonitrile, styrene-methacrylonitrile, ethyl acrylate, ethyl acrylate-vinyl acetate, ethyl acrylate-methyl methacrylate, ethyl acrylatestyrene, ethyl acrylate-butyl acrylate, butyl acrylate-acrylonitrile, and the like.

The addition polymers produced by the emulsion polymerization of the instant invention may be of the rubber or plastic type, and consequently their emulsions can be termed rubber latex or plastic latex. Rubber may be defined as a material that is capable of recovering from large deformations quickly and forcibly, and which can be (or already has been) modified to a state in which it is essentially insoluble (but can swell) in boiling solvent such as benzene, methyl ethyl ketone and ethanoltoluene azeotrope, or the like.

Rubber in its modified state, free of diluents, retracts within 1 minute to less than 1.5 times its original length after being stretched at room temperature (20-27 C.) to twice its length and held for 1 minute before release.

Plastic may be defined as a material that contains as an essential ingredient an organic substance of large molecular weight, is solid in its finished state, but at some stage in its manufacture or in its processing into finished articles can be shaped by flow.

Particularly preferred polymeric materials for the present invention are those of the carboxylated conjugated diolefin type. These include interpolymers of butadiene and styrene or butadiene and acrylonitrile with organic acids such as itaconic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, vinylacetic acid, ethacrylic acid, 2-ethyl-3- propylacrylic acid, beta-acryloxypropionic acid, sorbic acid, and the like.

The relative amounts of the aforesaid monomers vary widely, the proportions being well known to those skilled in the art. In the case of the carboxylated butadiene-styrene latexes the amount of polymerized butadiene and styrene varies from about 40 to 60 percent by weight based on the total weight of latex (i.e., 40 to 60 percent polymeric solids) and the amount of carboxyl component generally ranges from about 0.5 to 5 percent of the total polymerized monomers.

The emulsion solution, i.e., the aqueous solution of the oligomer, which may or may not be partially or completely neutralized, contains 20 to 60 percent solids and has a surprisingly low viscosity, e.g., 1-10 cps. at 10 to 20 percent solids. Generally 100 parts by weight of monomer for each 4 or 5 parts of solids in the emulsifier solution are introduced at a temperature of about 50 C. and at a pressure of 35-45 psig.

These conditions are typical and may be varied within wide ranges according to known emulsion polymerization and technology.

The range of typical emulsion polymerization recipes and reaction conditions are given in the following table.

TABLE Range of Typical Emulsion Polymerization Recipes and Reaction Conditions Parts by Weight The various modifiers, initiators, electrolytes and additives employed are conventional and are known to those skilled in the art. See e.g., Whitby, Synthetic Rubber, John Wiley & Sons, Inc., New York, 1954, pp. 224-283, the contents of which are herein incorporated by reference. As modifiers, aliphatic mercaptans are most commonly employed. lnitiators include redox systems, which generate free radicals, with or without complexing agents, and variable valence metal ions. Common initiators are persulfates, peroxides, hydroperoxides, ferricyanides, peroxamines, and diazo compounds such as diazo bis(isobutyronitrile).

After about to percent conversion of monomer to polymer is achieved, the pH of the emulsion is increased to 8.5-9.5 with a base such as ammonium hydroxide. Any unreacted monomer may be driven off by bubbling steam through the system. This stripping operation is slow and difficult when latexes prepared with conventional emulsifiers are involved because of foaming, which impedes the distillation of monomers and water and requires foam traps and a distillation pot, only partly full, to avoid loss of latex by foam carry-over. By contrast, latexes prepared with the oligomeric emulsifiers of the present invention can be stripped rapidly from a nearly full pot without the use of a foam trap, since they exhibit little or no foaming. This behavior of the oligomeric emulsified latexes is of obvious significance. While antifoaming agents can be used with conventional emulsifier latexes, these agents add to cost and may damage polymer properties by appearing in the polymer as a separate phase. Since stripping dilutes the latex, it is finally concentrated to about 50 percent solids. This operation, too, is greatly facilitated by the absence of foam in oligomeric emulsifier latexes and can be rapidly done by distilling off water from the latex in a distillation pot. Conventional emulsifier latexes can be only concentrated in apparatus which exposes a thin film of the latex, such as a multiple disc concentrator, because of foamy characteristics of the latex. The following examples will further illustrate our invention. Unless otherwise indicated, all parts are by weight.

EXAMPLE 1 Low molecular weight polymers (i.e., oligomers) of this invention and having the general formula, alkyl-S(O)-(acrylic acid),,-H or alkyl-S-(Oh-(acrylic acid) -H, were prepared in methanol using ammonium persulfate as the initiator and were oxidized with hydrogen peroxide after the methanol had been distilled off and replaced with water.

The general procedure employed was to add acrylic acid,

alkyl mercaptan, and methanol solvent to a reaction flask which was immersed in a thermostatted water bath and equipped with an addition funnel, a thermometer, an agitator, a water-cooled condenser and a nitrogen inlet. The solution was agitated, the nitrogen flow was commenced, and the content of the flask was heated. When the desired reaction temperature, in this example 29 C., was reached, a solution of the initiator in methanol was introduced at a controlled rate into the flask via the addition funnel. The reaction is exothermic, so that the temperature of the reacting system rises above that of the bath. When the reaction is complete, there is no difference between the temperatures of the reactants and the bath. The reaction system was then transferred to a distillation assembly which could be operated at reduced pressure and was equipped with a steam jet leading to the liquid phase of the distillation vessel. Water was added to the reaction system, the vessel was heated with external steam, and vacuum was applied. This caused methanol to appear in the distillation receiver. When this distillation had stopped the system was returned to atmospheric pressure and steam was introduced into the reactor through the jet. This caused water with traces of methanol to distill off as the temperature reached 100 C. The reaction system was cooled to about 50 C. and a mole of hydrogen peroxide, as a 30 percent aqueous solution, was added for each gram-atom of sulfur in the material. This addition of H which reacted to form the product, alkyl-S(O)- (acrylic acid),,-H, was effected slowly so that the resulting exotherm did not exceed a temperature increase of C. The system was kept at 60 C. for about 1 hour after the completion of the addition of the hydrogen peroxide, and was then cooled to room temperature. To maintain homogeneity of this aqueous solution of the oligomer at room temperature, it was necessary, in some cases, to neutralize some of the acid groups with potassium hydroxide or other basic material such as sodium hydroxide or ammonia. The product was converted to alkyl-S(O) -(acrylic acid),,-H by adding another mole of hydrogen peroxide for each gram-atom of sulfur and heating at 90-l00 C. for about an hour.

Run 1 Preparation of n-octylS(O)-acrylic acid) 1-l:

The following materials were added to the reaction flask:

288 g. (4.0 moles) acrylic acid 194.7 g. (1.33 moles) n-octyl mercaptan 207 g. methanol Following the procedure previously described, the reaction was initiated at the reaction temperature by introducing a 0.8% (Nl-14) S O /methanol solution at a rate of 7.4 g./hour. The reaction temperature reached 35 C. during the first 3.5 hours and gradually returned to the bath temperature. After 6 hours the addition of initiator solution was stopped. The reaction system was slightly hazy but fluid. Solids determination showed 99. 1 percent conversion of reactants to product.

Of this reaction system, 93.3 percent was transferred to the distillation vessel and methanol was removed following the previously described procedure. The product was cooled and 109 g. of 36.1 percent hydrogen peroxide were added. One hour after the exotherm was over, sufficient 20% KOH was added to neutralize 5 percent of the acid groups. The product was a clear solution with 3 1.4 percent solids.

Run 2 Preparation of n-Octy1S(O) -(acrylic acidh-H:

958.2 g. of the 31.4 percent solids solution of the product from Run 1 were placed in the distillation apparatus and 72.5 g. of 36.1 percent aqueous hydrogen peroxide were added. This system was then heated with external steam to 94 C. and then with internal steam to 98 C. and was kept at this temperature for 1 hour. On cooling, the solution showed a small amount of precipitate which was removed by filtration. The filtered solution had 18.9 percent solids.

The oligomers of Runs 1 and 2 of this Example were surface active, as shown by surface tension measurements on diluted aqueous solutions thereof, in which 5%, 15%, or 25% of their acid groups were neutralized with KOH. These data, given in Table 1, show that the alkyl-sulfone terminated oligomer (Run 2) is slightly more surface active, at the higher concentrations, than the alkyl-sulfoxide terminated oligomer (Run 1 TABLE 1 Surface Tension of Aqueous Solutions of n-Octyl-S(O)- (acrylic acid );-H and n-Octyl-S(O) -(acrylic acid );,-H at Various Concentrations and KOH Neutralization.

Following the procedure described in Run 1, 109.5 g. (0.75 moles) n-octyl mercaptan, 216 g. (3.0 moles) acrylic acid and 139.5 g. methanol were added to the reaction flask. The initiator, which was 0.8% (NH S O /methanol, was added over a 6 hour period and totalled 16.3 g. The conversion of reactants to product was 95.8 percent. 95.3 percent of this reaction product was then stripped and oxidized with 81 g. of 30 percent hydrogen peroxide. The final product, when 1 percent of the acid groups were neutralized with KOH, was a clear solution and had 29.2 percent solids.

Additional runs in which there were prepared R-S(O)- (acrylic S(O)-(acrylic acid),,-H, all using the same general procedure described above, are given in Table 2.

TABLE 2.PREPARATION OF RS(O)(ACRYLIC ACID)|,H

Run N0. 4 5 6 7 8 9 10 11 12 Carbon atoms in R 8 8 8 8 8 8 8 10 12 R configuratior. n n n n n p t n n Acrylic acid loaded, g 227 252 216 144 l 258 238 288 216 216 Mercaptan loaded, g 184 146 73 29 146 195 195 174 202 Methanol loaded, g.. 176 171 124 d 282 146 207 207 167 179 Initiator solution, g 40 45 12 d 32 30 33 24 20 Reaction time, hours 3.3 6.7 4. 3 7.0 5. 5 5. 5 5.0 4. 7 4. 5

Percent conversion l 93 07 99 97 82 95 85 94 94 Final solution percent solids 52 46 28 9 47 34 28 30 19 with Table 2 Continued Appearance 1 C C C n Methacrylic acid was used in lieu of acrylic acid.

attachment of sulfur): t is tertiary attachment of sulfur.

d Isopropyl alcohol was used. The initiator system was 1 g. lauroyl peroxide and 0.25 g.

N,N-dimethyl aniline.

e Initiator solution was 0.8% (NII4)2S2OI in methanol. 1 C is clear; H is hazy; M is milky.

EXAMPLE 11 Low molecular weight polymers (i.e., oligomers) of this invention and having the general formula n-alky1-S(O),.- (acrylonitrile),,-(acrylic acid),,-H were prepared in methanol or isopropyl alcohol using ammonium persulfate or lauroyl peroxide as the initiator and were oxidized with hydrogen peroxide before or after the alcohol had been distilled off and replaced with water.

The general procedure was to add the acrylic acid, acrylonitrile, n-alkyl mercaptan and methanol to a flask which was immersed in a thermostatted water bath and equipped as described in Example 1. The continuous addition of the ammonium persulfate initiator solution to cause the reaction to proceed and the concomitant changes in the temperature of the reaction system to the apparent completion of this oligomerization were also as described in Example I.

When lauroyl peroxide was used as the initiator, it was added dry to the reaction mixture, either all at one time or in a few increments. Usually the lauroyl peroxide was activated by the addition of N ,N-dimethyl aniline. The reaction system was oxidized with hydrogen peroxide using 1 or 2 moles of hydrogen peroxide per gram-atom of sulfur, either before the methanol had been distilled off and replaced with water, but preferably this oxidation was effected after the distillation. The distillation assembly was as described in Example 1, except that the internal jet could be raised so that a stream of air would impinge on the surface of the liquid in the pot. Since the reaction system as well as the product were not soluble in water until some of the acid groups had been neutralized, enough aqueous KOH solution to neutralize at least 70 percent of the acid groups was added to the reaction system at the time of transfer to the still. The contents of the pot were heated and most of the methanol was removed, either by reducing the pressure or by drawing air over the surface of the liquid in the pot. However, ultimately steam was introduced into the liquid and this caused water and traces of methanol to appear in the receiver with the pot temperature reaching the boiling point of water. The liquid remaining in the pot was cooled to about 50 C. and enough aqueous hydrogen peroxide was added to oxidize each sulfide to sulfoxide. An exotherm was observed upon this addition and 1 hour after it had subsided, the product, which had 20-50 percent solids and was macroscopically homogeneous, was removed. The sulfoxide was converted to the sulfone by adding to the solution 1 mole of aqueous hydrogen peroxide for each gram-atom of sulfur and heating at about 90 C. for about 1 hour.

Run 1-Preparation of n-octyl-S(O)-(acrylonitrile) -(acrylic acid ),;-H and n-octyl-S(O) -(acrylonitrileh-(acrylic acid) -H) The following materials were added to the reaction flask:

216 g. (3 moles) acrylic acid 159 g. (3 moles) acrylonitrile 54.8 g. (0.375 moles) n-octyl mercaptan 61.5 g. methanol Following the procedure previously described the reaction was initiated at 28 C. by introducing 0.8% (NI-{ 8 0 in methanol at such a rate that 1 19 g. had been added over 6.8 hours. The temperature of the reacting system was kept in the range of 3338 C., but during the last 1.5 hours, the bath temperature was raised to 35 C. The resulting transparent yellowish liquid weighed 628.6 g. and showed 97.8 percent conversion by solids determination. 508.3 g. of this reaction product was transferred to the still and enough aqueous KOH solution was added to neutralize 72 percent of the acid groups. The methanol was removed, first by drawing air over the surface of the liquid and then by introducing steam into the liquid. When the specific gravity of the distillate had reached 0.994, it was evident that the methanol removal was complete. The pot residue now weighed 1,460 g., was homogeneous, and contained 23.3 percent alkyl-sulfide terminated oligomer. A portion of this solution was diluted to 10 percent oligomer. which showed a pH of 5.7. By adding KOH to other portions and then diluting, 10 percent oligomer solutions were prepared at pHs of 6.0, 6.5, and 9.0. The sulfoxide and sulfone derivatives were prepared from these 10 percent solutions by adding the appropriate amount of hydrogen peroxide and heating with atmospheric steam for an hour. These oxidized product solutions were diluted to 8 percent oligomer.

Run 2Preparation of n-R-S(O) acrylonitrile),,-( acrylic acid), -H where R is a mixture of n-Octyl and n-Dodecyl in 99/1 Mole Ratio The following materials were added to the reaction flask:

121.0 g. (1.68 moles) acrylic acid 59.4 g (1.12 moles) acrylonitrile 10 percent of a mixture of 20.24 g. (0.1386 mole) n-octyl mercaptan and 0.28 g. (0.0014 mole) n-dodecyl mercaptan 56 g. isopropyl alcohol 1.4 g. lauroyl peroxide The reaction flask assembly was placed in a 50 C. thermostatted b ath and nitrogen flow was started. After 23 minutes the reaction started as indicated by a slight exotherm. The observations and additions are given in Table 3 TABLE 3 Observations and Additions in Run 2 of Example 11 Reaction of Mixed Other Time Temp. Conversion Mercaptans Manipulation, min.* C. by Solids Added Addition 162 48.0 59 200 10 15 g. isopropyl alcohol 230 48.0 79 20 g. isopropyl alcohol 234 26.2 g. acrylic acid and 2.67 g. mercaptan mix 251 10 10 g. isopropyl alcohol 277 10 300 47.7 78 305 10 10 g. isopropyl alcohol 360 86 38 g. isopropyl alcohol From start ofthe reaction.

The reaction mass was permitted to stand overnight and then showed 57.5 percent solids, which indicated 95.8 percent conversion. .For stripping, 228.7 g. of this reaction product, which contained 131.5 g. of the alkyl-sulfide terminated oligomer, was mixed with 33 g. of potassium hydroxide and 550 g. of water. This mixture was vacuum stripped at 90 C. and gave 100 ml. of clear distillate. The flask residue was diluted to 10 percent alkyl-sulfide terminated oligomer and this solution had a pH of 6.5 and was slightly hazy. This oligomer was converted to the alkyl-sulfone terminated oligomer by mixing 500 g. of the 10 percent solution with 8.3 g. of 30 percent hydrogen peroxide, heating in atmospheric steam for 1 hour, stripping off 10 g. of water, cooling, adjusting the pH. to 6.5 with 20 percent potassium hydroxide, and diluting to 10 percent alkyl-sulfone terminated oligomer.

That both the alkyl-sulfide and the alkyl-sulfone terminated oligomers were emulsifiers is demonstrated in Table 4, which gives surface tension measurements at various concentrations. The alkyl sulfide terminated oligomer appears to be more surface active than its oxidized derivative at the lower concentrations.

TABLE 4 Surface Tension of Various Aqueous Solutions of n-R-S- (acrylonitrile) -(acrylic acid), -H and Its Sulfone, Where R is a 99/ 1 Mole Mixture of n-Octyl and n-Dodecyl, at pH 6.5, KOH Neutralized Concentration 10% 1% 0.5%0. 1%

Surface Tension, d/cm.

(acrylic acid), -H 32 29 37 43 53 n-R-S(O)- (acrylonitrile),,- (acrylic acid),. .-H 3O 3O 44 49 59 59 Run 3 n-Decyl-S(O)-(acry1onitrile) ,(acrylic acid) H Following the procedure in Run 1, 288 g. (4 moles) acrylic acid, 106 g. (2 moles) acrylonitrile, 34.8 g. (0.2 mole) n-decyl mercaptan and 166.5 g. methanol were added to the reaction flask. This reaction system was brought to equilibrium with the 28 C. bath and the initiator solution (0.8% (Ni-1.0 8 0 in methanol) was added at a rate that effected the addition of 134.6 g. in 6.5 hours. The reaction temperature was kept in the 33-38 C. range, although during the last 2 hours of the reaction it was necessary to raise the bath temperature to 35 C. The reaction product weighed 721.4 g. and its solids content indicated that 98.0 percent conversion was reached. For removal of the methanol, 61 1.2 g. of this reaction product was placed in the still and 26.0 g. 85 percent KOH pellets dissolved in 700 g. water were added. This amount of base neutralized 72 percent of the acid groups. The methanol was removed by means of an air stream and steam until the specific gravity of the distillate was 0.998. The pot residue weighed 1374 g. and had 26.0 percent oligomer content. To oxidize the oligomer, that amount of this solution which contained 60 g. of the oligomer was diluted to 600 ml. with water and this solution was heated to 50 C. On addition of 3.6 g. of 30 percent hydrogen peroxide, an exotherm of 0.4 C. was observed. The pH of this solution was 5.7.

Following the procedure in Run 1, 216 g. (3 moles) acrylic acid, 159 g. (3 moles) acrylonitrile, 65.2 g. (0.375 mole) ndecyl mercaptan and 61.5 g. methanol were added to the reaction flask. This reaction system was brought to equilibrium with the 28 C. bath and the initiator solution (0.8% (NI-IQ S O in methanol) was added at such a rate that 142.6 g. had been added over 6.7 hours. The reaction temperature ranged from 30 to 36 C. for the first 4 hours of the reaction. During the last 2.7 hours, the bath temperature was raised to 3536 C. and the reaction temperature reached 38 C., then fell to 36 C. The reaction product weighed 641.5 g. and showed, by solids determination, a conversion of 95.8 percent. There were placed in the still 569.4 g. of this reaction product and 124.8 g. KOH dissolved in 668 g. water. The methanol was removed, first with an air stream and then by steam. The specific gravity of the distillate reached 0.998 when 400 ml. had been collected. There was 21.9 percent oligomer in the pot residue, which had a pH of5.7. This oligomer solution was diluted to 10 percent oligomer and heated to 50 C. There were added 6.1 g. 30 percent hydrogen peroxide, and an exotherm of 1.0 C. was observed. After 1 hour at 50 C., the reaction solution was cooled to room temperature. Run 5 Preparation of n-OctylS(0) -(acrylonitrile),,- (acrylic acid),,l-l by Oxidation with Ozone An aqueous solution of the oligomer, n-octyl-S- acrylonitrile) acrylic acid ),,-H, which was almost completely neutralized and stripped, contained 1 1.8 g. (8.14 millimoles) of the neutralized oligomer in 91 ml. of solution. To this was added 200 ml. of water, and it was then reacted with 16.3 millimoles of 0 contained in 0 in an ozonation vessel equipped with a Kl trap. It was necessary to add the O in onequarter portions and to allow the foam to settle before more was added. The 0 was absorbed quantitatively since there was no discoloration of the K1. The product was an aqueous solution of the n-octyl-sulfone-terminated oligomer.

EXAMPLE 111 Low molecular weight polymers (i.e., oligomers) of the invention having the general formula alkyl-S(O) (A),,-(acrylamide),,-H with (A) representing a polymerizable carboxylic acid, were prepared in isopropyl alcohol, lauroyl peroxide serving as the initiator, N ,Ndimethyl aniline serving as the activator, to give as an intermediate a precipitate which was washed with alcohol, dried in an air stream, dissolved in water and oxidized by hydrogen peroxide. The apparatus used for the oligomerization was described in Example 1. The product was a fine precipitate in this reaction system and was removed by filtration through paper. The retained precipitate was washed with isopropyl alcohol and dried by drawing air through it. For oxidation, the apparatus used for oligomerization was again employed. The dry powder was dissolved in water and placed in the reaction vessel. The solution reached equilibrium with the 50 C. bath and enough aqueous hydrogen peroxide was added to oxidize each sulfide linkage to sulfoxide. After cooling, the solution of the oligomer was ready for use.

Run 1Preparation of n-octyl-S(O)-(itaconic acid) (acrylamide), -H

The following maerials were added to the reaction flask:

512.2 g. (7.214 moles) acrylamide 104.2 g. (0.8015 mole) itaconic acid 58.5 g. (0.4008 mole) n-octyl mercaptan 12.0 g. lauroyl peroxide 2,525 ml. isopropyl alcohol The flask was placed in a 37 C. thermostatted bath, such initial placement serving as the reference time. The reaction temperature was 35 .2 C. at 35 minutes and 4 g. N,N-dimethyl aniline were added. At minutes, the reaction temperature reached 41.0 C. and 19.6 g. (0.1344 mole) n-octyl mercaptan were added. The reaction temperature was 438 C. at minutes and 6 g. lauroyl peroxide were added. N,N-dimethyl aniline (4 g.) was added at minutes, when the contents of the flask were at 44.5 C. The reaction temperature peaked at 450 C. between -160 minutes, then fell continuously and reached 37.0 C. at 255 minutes, and did not change during the next 30 minutes. The reaction system was vacuum filtered through paper. The precipitate was slurried in methanol which had been heated to 60 C., and was then filtered again. The precipitate was washed with 700 m1. methanol and dried overnight by drawing air through it. The next day, the precipitate weighed 627 g., which indicated a 90 percent yield. Some of the product was dissolved in water with enough calcium hydroxide to neutralize half of the acid groups to thereby prepare a 10 percent aqueous solution which had a 52.7 d/cm.

nun-in A..."

surface tension and thus was a surface active agent. The product (130.8 g.) was dissolved in 415 g. water and placed in an agitated flask in a 49.0 C. thermostatted bath. When the flask contents reached equilibrium with the bath, 7.54 g. 35 percent hydrogen peroxide was added and an exotherm of 0.7 C. was observed. After cooling, the solution contained 24.8 percent oligomer. The solution showed 41 d/cm. surface tension and 15 cps. viscosity.

Run 2 Preparation of n-dodecyl-S(O)-(itaconic acid) (acrylamide) -H There were placed in a crown cap soda bottle, 63.9 g. (0.9 mole) acrylamide, 13.0 g. (0.1 mole) itaconic acid, 10.1 g. (0.05 moles) n-dodecyl mercaptan, 1.5 g. lauroyl peroxide, and 275.7 g. isopropanol. The vapor phase in the bottle was flushed with nitrogen and the cap attached. The bottle was rotated, as the spoke in a wheel, for 24 hours in a 50 C. thermostatted bath. The reaction system was vacuum filtered and the precipitated product was washed with 300 ml. isopropyl alcohol and 300 ml. acetone. The product was dried by drawing air through it for 24 hours. It weighed 84.4 g., which indicated a 97 percent yield. This product (52.0 g.) was dissolved in 301.4 g. water and placed in an agitated flask which was located in a 490 C. bath. When the contents of the flask were at the bath temperature, 2.84 g. of 35.8 percent aqueous hydrogen peroxide was added and an exotherm of 04 C. was observed. After one hour the solution, which contained 14.7 percent oligomer, was removed and bottled. The solution had 44 d/cm. surface tension and 12 cps. viscosity.

Run 3Preparation of n-octy1-S(O)-(itaconic acid) (acrylamide), -H There were placed in a reaction flask 74.7 g. 1.052 moles) acrylamide, 31.6 g. (0.263 mole) itaconic acid, 9.6 g. (0.0658 mole) n-octyl mercaptan, 2.0 g. lauroyl peroxide, and 460 ml. isopropyl alcohol. At the reference time, the flask was placed in a 400 C. thermostatted bath. N,N-dimethyl aniline 1.3 g.) was added at 18 minutes. The reaction temperature rose to 41-42 C. and at times of 50, 87 and 133 minutes, 1 g. lauroyl peroxide and 0.7 g. N,N-dimethyl aniline were added. At 220 minutes the reaction system was vacuum filtered and the precipitate was dried in an air stream to a constant weight of 95.9 g, which indicated 82.7 percent yield. This product (29.0 g.) was dissolved in 203 g. water and placed in an agitated flask which was located in a 490 C. bath. An exotherm of 04 C. was observed when 1.5 g. of 35.8 percent aqueous hydrogen peroxide were added to the flask. The reaction product was kept in the flask for 1 hour and showed 12.75 percent oligomer solution. This solution had 38 d/cm. surface tension and 10 cps. viscosity.

Run 4-Preparation of n-octyl-S(O)-(itaconic acid) (acrylamide) -H There were charged to the reaction flask 503.2 g. (7.087 moles) acrylamide, 102.4 g. (0.7875 mole) itaconic acid, 28.7 g. (0.1969 mole) n-octyl mercaptan, 11.8 g. lauroyl peroxide, and 2,481 ml. isopropyl alcohol. At the reference time, the flask was placed in a 40 C. thermostatted bath. After 25 minutes, 4 g. N,N-dimethyl aniline were added. The reaction temperature reached 40.2 C. at 95 minutes and 4 g. N,N- dimethyl aniline were added. At 120 minutes the reaction temperature peaked at 42.2 C. and then fell to 36 C. at 380 minutes. The reaction product was removed by vacuum filtration, washed with 1,250 ml. acetone and dried in an air stream to a weight of 544 g. compared to the theoretical of 634.3 g. This product (100.5 g.) was dissolved in 410 g. water and placed in an agitated flask in a bath thermostatted at 490 C. The addition of 2.96 g. of 35.8 percent aqueous hydrogen peroxide produced an exotherm of 07 C. The resulting solution contained 20.2 percent oligomer, and had 34 d/cm. surface tension and 8 cps. viscosity.

Run 5Preparation of n-octyl-S(O)-itaconic acid) -(acrylamide), -l-l In a reaction flask were placed 408.0 g. (5.7464 moles) acrylamide, 60.6 g. (0.4659 mole) itaconic acid, 60.5 g. noctyl mercaptan, 15.5 g. lauroyl peroxide, and 2,586 ml. isopropyl alcohol. The flask was placed in a bath thermostatted at 40 C. at the reference time. At 33 minutes, 2.4 g. N,N-dimethyl aniline were added. The reaction temperature increased to 420 C. at minutes and 2.4 g. N,N-dimethyl aniline were added. The peak reaction temperature of 43.5 C. was reached at 1 15 minutes and then it fell continuously until 36.0 C. was reached at 270 minutes. The precipitated product was removed by vacuum filtration, washed with 1,300 ml. acetone and dried in an air stream to a weight of 400 g., the theoretical yield being 529 g. 106.0 g. of this product were dissolved in 420 g. of water and placed in an agitated flask in a 49.0 C. thermostatted bath. Upon the addition of 7.87 g. of 35.8% aqueous hydrogen peroxide an exotherm of 0.7 C. was observed. The resulting solution contained 20.9% oligomer, the solution having 42 d/cm. surface tension and 13 cps. viscosity.

Run 6Preparation of t-octyl-S(O)-(itaconic acid) W (acrylamide), -H

In a reaction flask were placed 96.5 g. (1.36 moles) acrylamide, 19.6 g. '(0. 151 moles) itaconic acid, 11.0 g. (0.076 moles) t-octyl mercaptan, 2.27 g. lauroyl peroxide and 476 ml. isopropyl alcohol. The flask was placed in a 40 C. thermostatted bath at the reference time. At 25 minutes, 0.3 g. N,N-dimethyl aniline was added. At 75 minutes, the reaction temperature had reached 40.0 C. and 0.3 g. N,N-dimethyl aniline was added. Lauroyl peroxide (2.2 g.) was added at 95 minutes when the temperature was 41.0 C. At 1 10 minutes, 0.7 g. N,N-dimethyl aniline was added. The reaction temperature peaked at 44.4 C. at minutes. At minutes, 2.2 g. lauroyl peroxide was added and at minutes, 0.7 g. N,N- dimethyl aniline was added. The reaction temperature fell to 395 C. at 230 minutes. The product was removed by filtration, washed with 475 m1. isopropyl alcohol, reslurried with 476 ml. isopropyl alcohol (previously heated to 60 C.), filtered, washed with 475 ml. isopropyl alcohol, and dried by an air stream to a weight of 121.8 g. This compares to a theoretical yield of 127.1 g. To 30.0 g. of this product were added 21 1 g. of water and a solution was formed. This solution was placed in a 485 C. thermostatted bath and when the contents were at constant temperature, 1.70 g. of 35.8 percent aqueous hydrogen peroxide were added. An exotherm of 04 C. was observed. The resulting solution contained 12.76 percent oligomer. This solution had 37.4 d/cm. surface tension and 12 cps. viscosity.

Run 7Preparation of n-C /C Alkyl-S(O)-(acrylic acid),-

(acrylamideM-H The following ingredients were placed in a reaction flask: 100 g. (1.408 moles) acrylamide, 25.3 g. (0.352 mole) acrylic acid, 12.5 g. (0.0858 mole) n-octyl mercaptan, 0.44 g. (0.0022 mole) n-dodecyl mercaptan, 1.3 g. lauroyl peroxide, and 634 ml. isopropyl alcohol. The flask was placed in a bath thermostatted at 40 C. at the reference time. At 20 minutes, 0.2 g. N ,N-dimethyl aniline was added. The reaction temperature increased to 445 C. at 70 minutes and 0.2 g. N,N- dimethyl aniline was added. The temperature peaked at 45.4 C. and 82 minutes. At 92 minutes, 0.7 g. lauroyl peroxide was added. At 100 minutes, 0.2 g. N,N-dimethyl aniline was added. The reaction temperature had fallen to 405 C. at 200 minutes. The product was filtered off and washed with 634 ml. isopropyl alcohol. The product was dried in an air stream, the amount of dried product indicating a 96 percent yield. 30.0 g. of this product were dissolved in 210 g. water. At 49.0 C., 1.81 g. of 35.8% aqueous solution of hydrogen peroxide was added. An exotherm of 04 C. was observed. The finished solution contained 12.5% oligomer. This solution had 32 d/cm. surface tension and 5.5 cps. viscosity.

The following examples illustrate the use of our oligomers in emulsion polymerization.

EXAMPLE IV Part A To conduct the emulsion polymerization, 24 fluid ounce soda bottles containing the polymerization ingredients were fitted with a crown cap having a small hole in the center. The

metal cap was fitted with a self-sealing rubber gasket so that upon addition of the materials or removal of samples by use of a hypodermic ensemble, the cap would be self-sealing. A plurality of these bottles were rotated, as spokes of a wheel, in a thermostatic bath at 50 C. at l l revolutions per minute. Prior to capping, the bottles were purged of oxygen by the introduction of slight excess of butadiene which was allowed to evaporate. The emulsifier used was of the formula:

L (EOOHJ;

this being a preferred emulsifier. It was dissolved in water and sufficient potassium hydroxide was added so as to neutralize 67 percent of the acid groups.

companied by good stability in the stripper.

The above latex is considerably superior to those obtained using conventional emulsifiers, such as alkyl benzene sulfonates which, at 50 percent solids, have a surface tension of 3040 d/cm. and readily form a foam on agitation, which foam interferes with finishing and use.

Part B TABLE 6.--POLYMERIZATION PERFORMANCE AND LATEX PROPERTIES USING n-OCTYLS(O)-(ACRYLIC ACID) -H A'I VARIOUS LEVELS AND PERCENT NEUTRALIZATION AS THE EMULSIFIER Run Number." 1 2 3 4 5 6 7 8 .1

Oligomer parts... 3 4 5 3 4 5 3 4 5 Percent neutralize 10 l0 10 31 31 31 53 53 53 Hours to 100% convo 21 21 16 21 16 lti 21 21 '31 Coagulurn, per hundred 111 0.1 0.0 0.0 0. 37 0.3 0.3 0.6 0.4 0. 5 Surface tension, rl./cm.... 60 56 54 G4 64 64 64 66 67 Turbidity..." 1.0 0. 7 0, 5 0. 7 0. 3 0. 2 1.0 0. 4 0. 3 Brookfield viscosity, cps. at 48-50% solids v 100 195 78 143 105 35 78 120 Latex pH 4. 4 4. 4 5. 0 5. 1 5.0 5. 3 5. 4 5. 5

The polymerization ingredients, listed in Table 5, were placed in the bottle, in amounts, as grams, equal to twice the indicated figures.

TABLE 5 Emulsion Polymerization Recipe for a Carboxylated Butadiene Styrene Latex After 22 hours at C. the conversion of monomer to 50 polymer was virtually complete, as was shown by a vacuum inside the bottle when a hypodermic needle was inserted through the hole in the cap. The pH of the latex was raised to 9.2 with aqueous ammonia. The latex was then placed in a stripper, and was heated with agitation, but without vacuum, to 90 C. Steam, at 100 C., was bubbled through the latex. Water and residual monomer were distilled off until about 100 grams were collected. Steam introduction was then discontinued and a vacuum was applied to further concentrate the latex. During these finishing operations almost no foaming occurred, so that these steps could be accomplished rapidly without foam traps. No coagulum was formed, which indicated thAt the latex was stable to thermal and mechanical forces. The latex had the following composition and properties: no grain microfloc or coagulum; solids 52.5 percent; pH 6.2; surface tension 73 d/cm.; Brookfield viscosity 180 cps.; and turbidity 0.53.

The above properties clearly show that a highly desirable latex was formed. The turbidity is not too high for optimum usage, and yet the viscosity is of satisfactory value for efficient transfer. The solids content is high enough for economical production and transportation. The high surface tension, which facilitates finishing operations and eliminates the need for antifoaming agents since the latex does not foam, is ac- 75 The above data show that notwithstanding the variations in the amount and degree of neutralization of the oligomer, the reaction time is short, the coagulum and latex viscosity are always low, and the surface tension is high. This is the desired trend for each of these parameters. The latex turbidity varies from 0.21 to 1.02, which is a satisfactory region, so that this oligomer has the desired quality of giving good performance and latex properties over a wide range of imposed variables.

The stability of latexes produced by Runs 2, 3, 5, and 6 was demonstrated by adding, to 100 parts of latex solids, 300 parts of dry calcium carbonate. The latex pH was raised to 9 with ammonia and sufiicient water was added such that the solids of the mixture was 68 percent. Other materials in the system were a polyacrylate thickener to raise the viscosity, and for stability 1 part Na.,P 0 plus 1 part sodium salt of condensed naphthalene sulfonic acids. In this test none of the latexes produced coagulum. Thus, they showed satisfactory stability for commercial use with fillers.

Stability to filler without the use of Na P O, and the sodium salt of condensed naphthalene sulfonic acid was accomplished by increasing the itaconic acid level from 1 to 1.5 and decreasing the styrene from 59 to 58.5, and using 5 parts of the oligomer, which was 25 percent neutralized, in the polymerization recipe of Part A. The latex showed only 0.1 part coagulum per 100 parts monomer, had 0.29 turbidity, and at 52 percent solids had only 1 l0 cps. viscosity. These are outstanding properties for a latex. The pH of the latex was raised to 7 with KOH, it was heated to above C. in a distillation apparatus, and atmospheric steam was introduced into the latex to co-distill ofi' residual monomer with the water.

Under these conditions, a latex prepared using a conventional alkylbenzene sulfonate emulsifier will foam, and the flow of steam is kept low to prevent this foam from entering the receiver. The slow flow of steam and long time required to remove residual monomers dilutes the latex from 50 percent solids to as low as 20 percent solids. It is necessary to concentrate to higher solids for filler stability test. By contrast, with the instant latex a rapid flow of steam is effected since there is almost no foaming, and since removal of residual monomer is accomplished in a short time, the latex is only diluted to 45 percent solids from the original value of 50 percent. At this solids the latex is used in the tiller stability test without concentration, even after raising the pH to 9 with KOH. The system is stable without the use of the aids mentioned previously. Since these aids are hydrophilic it is considered that the Part C Data are hereinafter presented to show that the instant oligomer forms a latex which, for a given value for turbidity and solids, has a lower viscosity than a latex prepared using as the oligomer n-ctyl-S-(acryl0nitrile) -(acrylic acid) -H. It is to be noted that as the turbidity decreases, i.e., as the latex particle size decreases, a given latex type at a certain per cent solids, shows an increase in viscosity. It is important for a latex to be fluid so as to avoid loss through hold-up in transfer, so that lower viscosity is considered to be a property of distinct utility and advantage. In Table 7 the latexes were prepared using the recipe given in Part A of this example. The data for the oligomer, R-S-(O)-(acrylic acid);,, is from Table 6. All solids are in the 4850 percent range,

TABLE 7 Viscosity of Latexes Prepared Using n-Octyl-S(O)-( acrylic acid) -H or N-Octyl-S-(acrylonitrileh-(acrylic acid) -H These data show that the instant oligomer produces latexes with much lower viscosities than the reference oligomer.

Part D the latter oligomers as emulsifiers in the formations of latexes, as set forth in U.S. application, Ser. No. 562,097, filed July 1, 1966 and in U.S. application, Ser. No. 562,098, filed July 1, 1966, may be accompanied by in situ oxidation. The following data are presented to compare pre-oxidation and whatever in situ oxidation may take place.

The polymerization recipe was identical with that given in Part A of this example. The oligomer was also the same except that a portion of it is not oxidized. There is enough potassium O persulfate to oxidize 34 percent of the oligomer in the recipe.

The data are presented in Table 9.

The data of Table 9 show that complete pre-oxidation of the oligomer gives superior results to partial in situ oxidation. The latter causes lower conversions and more coagulum, neither of which is desirable in latex technology.

Information on partial pre-oxidation is given in Table 10 for a polymerization identical with that of Part A of this example. Here the same oligomer was used except that 33percent and 67 percent preoxidation samples were used. The oligomer was As shown hereinafter, the preparation of a latex using n 25 percent neutralized with KOHin allcases. octyl-S-(O)-acryhc ac1d) -H as the emulsifier rather than noctyl-S(O) -acrylic acid) -I-I, results in reduced coagulum TABLE 0 without significant changes in other properties. It is important to minimize coagulum because (1) it represents waste of raw l 2 r i s matena S and the e S 10 s of pfoducnon i due to the Effect of Extent of Pro-Oxidation of Oligomer on need for more frequent cleaning of equipment. The

. Polymerization Performance polymerization recipe was the same as that given in Table 5 except that either 4 or 5 parts of the oligomer were used. The Run No. 7 8 9 reactions were run for 64 hours at C. and all reached 50 98-100 percent conversion. The results are given in Table 8, Premxidation and show that use of the sulfoxide oligomer produced less ofoligomer 33% 67% coagulum. Conversion 96% 97% 100% TABLE 8.PROPERTIES 0F LATEX AS INFLUENCED BY ALKYL- SULFOXIDE OF ALKYL-SULFONE TERMINAIED OLIGOMERS AS POLY- ME RIZAIION EMULSIFIERS Coagulum parts per Brookfield viscosity,

100 monomer cps. Turbidity Oligomer type Sulfoxide Sulfone Sulfoxide Sulione Sulfoxide Sulfone 5% neutralization of oligomer:

4 parts oligomer... 0.2 0.5 103 0. 4 0. 6 5 parts 0lig0mer 0.0 0.4 143 0. 4 0. 4 15% neutralization of oligomer:

4 parts olig0mer 0. 3 0. 4 200 138 0.3 0. 4 5 parts 0lig0mer 0.2 0. 4 288 210 O. 2 0. 4 25% neutralization of oligomer:

4 parts oligomer. 0.2 0, 3 230 0. 2 0. 3 5 parts oligomer..." 0.2 0.2 380 315 0. 2 0.2

Part E Hours 64 64 64 The oligomers of the instant invention differ from the gg fgg abzz s 2 24 0 61 0 40 oligomers which are the subject of U.S. application, Ser. No. Turbidity 547,743, filed May 5, 1966, by the oxidation step. The use of 75 The data in Table 10 show a decrease in coagulum as the extent of pre-oxidation increases. This efiect is important in efficient latex manufacture, inasmuch as coagulum wastes raw material and will ultimately increase maintenance because the reaction vessels will have to be cleaned.

EXAMPLE V Following the procedure and using the polymerization formulation set forth in Example IV, Part A, Table 1 1 shows the use of various oligomers, of the R-S-( O)-( acrylic acid),,-H type, as emulsifiers.

Part B TABLE 13 Effect of Type of Oxidation of Oligomer and Persulfate Level TABLE 11. IOLYMERIZATION F ITACONIC ACID/BUTADIENE/S'IY- RENE (IMO/U) LATEX ON RS(O)(ACRYLIC ACID)bH TYPE ()LIGOMERS Run Number 1 2 3 4 6 7 O ligomer:

R l c 11-Cg {PCB n-Ci n-Cg p-Cs t-Ca "fl-C i l) 2. 5 3. 5 4 6 3 3 Percent of acid groups neutralized with KOH 25 31 42 25 50 25 Latex:

Percent conversion v 98 99 97 98 32 22 99 Hours 64 64 64 21 64 64 64 Coagulum, parts per 100 monomer 0 0. 5 0. 5 Turbidity t 1.3 0.2 0.3 Brookfield viscosity, cps 630 80 Surface tension, d./cm 64 72 63 The data in Table 1 1 show that with R of the R-S(O)-( acrylic acid ),,-H type oligomer either primary or tertiary octyl, low ultimate conversions are obtained. Since this behavior represents effort required to reclaim the unused raw materials, it is not conductive to optimum efiiciency of latex manufacture. if R is n-decyl, the latex appears to be as satisfactory as when R is n-octyl. Values of b at 2.5 and 6.0 give turbidities which are too high for economical manufacture since their cycle time is long. The best properties of the latex occur when b is in the 3 to 4 range.

EXAMPLE VI The use of oligomers of the type, R-S(O)-(acrylonitrile),,- (acrylic acid),,-H, with R being a normal alkyl, as emulsifiers in latex preparation is described in this example. The procedure was the same as that in Example IV, Part A. The polymerization recipe differed from that given in Table 5 by increased potassium persulfate (1.25) and increased water (120).

Part A The.' oligomers that were used in the polymerizations described hereinafter were represented by n-octyl-S(O) (acrylonitrile acrylic acid ),;-H, where c is l or 2, and by the unoxidized sulfide precursor. In the polymerization recipe there is more than enough potassium persulfate to oxidize this precursor to the alkyl-sulfoxide terminated oligomer. The data are presented in Table l2.

in Polymerization Recipe on Latex Performance and To sull'oxide terminated oligomer The foregoing data show that the polymerization rate on the unoxidized precursor is greater than on the pre-oxidized oligomer. This is an important difference as regards economical latex manufacture. The ability to use less initiator, e.g., K 8 0, with the pre-oxidized oligomer is of distinct value, since reduction its amount would tend to improve water re sistance of the ultimate product.

PartC The preparation of R-S(O) -(acrylonitirle acrylic acid) -H, where R is a 99/ 1 mole ratio mixture of n-octyl and TIONS OF THESE OLIGOMERS, ON LATEX PROPERTIES Run number 1 2 3 4 5 6 7 8 9 0 Val 0 1 2 0 1 2 0 1 2 pH 5.7 5.7 5.7 6.0 6.0 6.0 6.5 6.5 6.5 Latex:

Percent conversion .d. 100 100 100 100 100 100 100 100 100 m, arts er hundre Coagulu p p 0.6 0.0 0.0 0.1 0.0 0.0 0. 0 0.0 0.0 1. 8 2. 3 0. 9 2. g 2. g Brooksfield viscosity cps 460 50 180 5 5 Surface tension, dJcIii 76 78 76 73 78 74 75 72 76 1 Of the aqueous solution. Oxidation of the alkyl-sulfide terminated oligomer to sulfoxide or sultone was conducted at this pH. See Example II, Run 1.

The above data show that the pre-oxidized oligomers produce higher turbidity latexes at the three given pHs, than does the unoxidized precursor. While other properties are similar, this change in latex particle size is an important one and indicates process differences.

n-dodecyl, and its unoxidized precursor was described in Example ll, Run 2. Both oligomers had their pH adjusted to 6.5 with KOH and were used in a polymerization at 4 parts at 50 C. The other ingredients in the polymerization were butadiene (40 parts), styrene (59 parts), itaconic acid (1 part), along EXAMPLE VII Use of the oligomer, n-decyl-S(O)-(acrylonitrileh-(acrylic acid),,-H, as emulsifiers in latex preparation is described in this example. The procedure was the same as in Example IV, Part A. The polymerization recipe differed from that given in Table by increased potassium persulfate (to 1.25) and.increased water (to 120). The data is given in Table 14, the performance of the unoxidized oligomer also being included.

TABLE 14 Effect on Polymerization Performance and Latex Properties of the Oligomeric Emulsifier, n-decyl-S(O)-(acrylonitrile (acrylic acid) -I-I and its unoxidized precursor Run No. 1 2 3 4 5 6 Preoxidation of Oligomer No Yes No Yes No Yes TABLE 16.EFFECT PROPERTIES OF Run No. l 2 3 4 5 6 Pre-oxidation of Oligomer No Yes No Yes No Yes Oligomer pI-l (KOl-I Neutralized) 5.9 5.6 6.5 6.5 9.0 9.0 Conversion 99% 100%100% 100% 100% 100% Coagulum, parts per 100 monomer 0.31 0.03 0.08 0.03 0.06 0.02 Turbidity 0.39 0.72 0.80 0.79 0.58 0.60 Brookfield Viscosity, cps. 170 250 230 330 280 420 Solids 47 48 47 47 47 47 These data establish that at the lower pH the unoxidized precursor forms a latex with lower turbidity than that of the pre-oxidized oligomer. At other pI-Is, the two processes are equivalent in latex properties. All latexes have turbidity,

viscosity and eoagulum values which have utility in latex manufacture.

EXAMPLE IX Use of oligomers of the type, R-S(O)-(A) -(acrylamide) H, as emulsifiers in latex preparation is described in this example. R is an alkyl group and A is either acrylic acid or itaconic acid. The procedure was the same as in Example IV, Part A, and the polymerization recipe was as given in Table 5, except that 5 parts unneutralized oligomer were used. The performance of the unoxidized oligomer also is given. The data is given in Table 16.

ON POLYMERIZATION PERFORMANCE AND LATEX THE OLIGOMER, R-S(O)-(A)s(ACRYLAMIDE) H AND ITS UNOXIDIZED PRECURSOR IN UNNEUTRALIZED STATE Coagu- Percent 111m, parts Brookfield Run Preoxiconper 100 viscosity, R No. A a b dation version monomer cps.

l I 2 99 0.04 220 2 I 2 99 0.19 340 3 I 2 100 200,000 4 I 2 1 5 I 4 99 0.30 2,000 6 I 4 93 0.50 2,005 7 I 4 100 0.16 200 8 I 4 100 0.14 310 9 I 1.1 100 0.12 1,140 ll-Cg 10 I 1.1 .10 0.42 1,800 t-Cs 11 I 2 100 1.07 124 L-Cs 12 l 2 J0 0.110 104 l 100% gel. I=Itac0nlc acid; A=Acryllc acid.

EXAMPLEX (KOH neutralized) 5.7 5.7 6.5 6.5 9.0 9.0 z fgg g 3 :6 3 3 6 In this example, the oligomer type was the same as used in Solids 41% 46% 44% 48% 44% 48% Example IX. The polymerization recipe was changed to: B kfi ld styrene 70, acrylomtrlle 30, potassium persulfate 1.25, un- ViSCOSitMCPS- 930 4950 2325 10.000 3300 19.500 neutralized oligomer 5, sodium carbonate 0.4, tetrasodium These data show substantial differences in turbidity only at the lowest pH. Another difference between pre-oxidation and use of unoxidized precursor appears to be the higher ultimate conversion attained with the former, notwithstanding that there is enough potassium persulfate in the recipe to completely oxidize in situ the latter.

EXAMPLE VIII This example is similar to Example VII, except that the oligomer was n-decyl-S(O)-(acrylonitrile) -(acrylic acid) H. The data is given in Table 15.

TABLE 15 Effect on Polymerization Performance and Latex Properties ofthe Oligomeric Emulsifier, n-decyl-S(O)-( acrylonitrile) (acrylic acid ),.,-H and its Unoxidized Precursor ethylenediamine tetraacetate 0.05, tertiarty dodecyl mercaptan 0.15 and water 120. The data are given in Table 17.

TABLE 17 Effect on Polymerization Performance and Latex Properties of the Oligomer, R-S(O)-(A) -(acrylamide),,-H and Its Unoxidized Precursor 9 l n-C 1.1 13.9 Yes 98% Nil 1 n-C 1.1 13.9 No 98% Nil 1 l l t-Cg 2 18 Yes 88% Nil 12 l t-C 2 18 No All Gel I is ltaconic acid, A is acrylic acid.

" 'phm stands for parts per 100 monomer.

'The R group in this oligomer was 0.975 mole fraction n-octyl and 0.025 mole fraction n-dodecyl.

Variations can of course be made without departing from the spirit of my invention.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. An oligomer having a molecular weight greater than 200 to less than 5,000 and having the formula:

wherein R is straight chain primary, branched chain primary, secondary, or tertiary alkyl group having from five to 20 carbon atoms; R and R are hydrogen, methyl, ethyl or -COOH; R and R are hydrogen, methyl, ethyl, COOH or CH COOH; Y is COOH, CONl-l OCH OC H or -CH OH; a b is from 2 to 50; a/a-l-b is greater than zero and not greater than 0.6; and Z is oxygen or nothing; and, where said oligomer contains at least one carboxylic acid group, the said group may be in the form of the free acid or a water soluble salt thereof.

2. The oligomer of claim 1 wherein Z is oxygen.

3. The oligomer of claim 1 wherein Z is nothing.

4. The oligomer of claim 1 wherein R is an alkyl group having from six to 12 carbon atoms.

5. The oligomer of claim 1 wherein R is a primary of secondary alkyl group having from six to 12 carbon atoms; R,, R and R are hydrogen, R is hydrogen or methyl, and a b is from 4 to 50.

6. The oligomer of claim 5 wherein R is a normal alkyl group having from seven to l 1 carbon atoms, a b is from 12 to 30, and a/a-l-b is from 0.2 to 0.55.

7. The oligomer of claim 1 wherein the water soluble salt is an ammonium, alkali metal or alkaline earth metal salt.

8. The oligomer of claim 1 wherein at least one carboxylic acid group is present or the sodium, potassium, ammonium, calcium, zinc, magnesium, barium, a lower alkyl substituted amine, or a lower alkanol substituted amine salt of said carboxylic acid group.

9. The oligomer of claim 6 wherein R is a normal alkyl group having from eight to 10 carbon atoms, a b is 12 to 30, and a/a-l-b is 0.5.

10. The oligomer having the formula: n-octyl-S(O),, (CH CHCN) (CH CR,COOH) H, wherein R is hydrogen or methyl and a is 1 or 2.

11. The oligomer having the formula: n-decylS(O),,- (CH CHCN) (CH CR COOH) -l-l, wherein R is hydrogen or methyl and a is l or 2.

12. The oligomer having the formula: n-decylS(O) (CH CHCN) cq(CH CR,COOH)QQH, wherein R is hydrogen or methyl and a is 1 or 2. 

2. The oligomer of claim 1 wherein Z is oxygen.
 3. The oligomer of claim 1 wherein Z is nothing.
 4. The oligomer of claim 1 wherein R is an alkyl group having from six to 12 carbon atoms.
 5. The oligomer of claim 1 wherein R is a primary of secondary alkyl group having from six to 12 carbon atoms; R1, R2 and R3 are hydrogen, R4 is hydrogen or methyl, and a + b is from 4 to
 50. 6. The oligomer of claim 5 wherein R is a normal alkyl group having from seven to 11 carbon atoms, a + b is from 12 to 30, and a/a+ b is from 0.2 to 0.55.
 7. The oligomer of claim 1 wherein the water soluble salt is an ammonium, alkali metal or alkaline earth metal salt.
 8. The oligomer of claim 1 wherein at least one carboxylic acid group is present or the sodium, potassium, ammonium, calcium, zinc, magnesium, barium, a lower alkyl substituted amine, or a lower alkanol substituted amine salt of said carboxylic acid group.
 9. The oligomer of claim 6 wherein R is a normal alkyl group having from eight to 10 carbon atoms, a + b is 12 to 30, and a/a+ b is 0.5.
 10. The oligomer having the formula: n-octyl-S(O)a-(CH2-CHCN)8-(CH2CR1COOH)8-H, wherein R1 is hydrogen or methyl and a is 1 or
 2. 11. The oligomer having the formula: n-decyl-S(O)a-(CH2CHCN)8-(CH2CR1COOH)8-H, wherein R1 is hydrogen or methyl and a is 1 or
 2. 12. The oligomer having the formula: n-decyl-S(O)a-(CH2CHCN)10-(CH2CR1COOH)20-H, wherein R1 is hydrogen or methyl and a is 1 or
 2. 